Favoured methods used by his secret police included eye-gouging; piercing of hands with an electric drill; suspension from a ceiling; electric shock; rape and other forms of sexual abuse; beating of the soles of feet; mock executions; extinguishing cigarettes on the body, and acid baths.

A case history seen by the Mail shows that Al-Byati arrived in Britain on a six-month visitor visa in January 2000, nine years after the end of the first Gulf War which left Saddam in power.

Officials twice extended his leave to stay so he could undertake clinical attachments as a doctor.

In January 2004, by which time Iraq had been invaded again, a work permit was granted and he was employed at a hospital in Wolverhampton until February 2007.

At this point, Al-Byati claimed asylum. In his witness statement he says he worked for the Iraqi Intelligence Agency.

In March 2007, while being interviewed by UKBA, Al-Byati stated that he patched people up after torture and was aware that the victims were returning to torture, but did not feel he could do anything about it.

A month later, his file was referred to the war crimes unit.

In 2008, he applied for permission to work as he had the offer of a four-month contract with a hospital in Wales.

Normally, asylum seekers are barred from working. But there is an EU directive that allows an asylum seeker to work if the case has not been dealt with for 12 months or more through no fault of their own.

As a result, since 2008 Al-Byati has been working full-time as a locum registrar and occasionally as a consultant in the West Midlands.

The scandal was unearthed because UKBA has just given advice to its chief executive that Al-Byati should be granted leave to remain, or asylum.

At this point, the stunned Home Secretary was made aware of what was happening. Leave to remain has not been granted.

A senior source said: ‘The Home Secretary was horrified to find out that this has been allowed to carry on for so long. She dragged the acting chief executive into her office and he got the hairdryer treatment.’

The source continued: ‘We always knew that Labour let the immigration system get out of control but we were genuinely stunned. The Home Secretary is seriously considering having a review of the way the entire agency works.’

The Home Secretary has also been demanding answers from the GMC, which is supposed to check a doctor’s background, but has been frustrated by slow response.

One perversity of the asylum system is that the worse the crimes an applicant has been involved in, the more likely he is to be allowed to stay.

He can claim that, if sent back to the country where the offences were committed, he may be subjected to degrading treatment, which is not allowed under the Human Rights Act.

In the past some asylum seekers have made their past exploits sound worse to bolster their case.

A report last year branded Britain a ‘safe haven’ for war criminals with hundreds of people wanted for murder and torture living here free from prosecution.

The GMC said last night: ‘We have recently become aware of concerns regarding this doctor.’

By Fay Schlesinger

‘

Mohammed Kassim Al-Byati last night told how he witnessed the horrifying injuries inflicted by Saddam Hussein’s henchmen – before patching up the victims and leaving them in the hands of their tormentors.

Sitting in the living room of the detached four-bedroom house he shares with his wife and three children in a leafy suburb of Birmingham, the grossly overweight doctor launched into a staunch defence of his actions.

With Wimbledon showing on the television screen beside him, he insisted: ‘What I have done was my normal doctor duty...which I am doing here (in Britain) every minute.’

Since 2002, Al-Byati says he has worked at hospitals across the country, including Wolverhampton, Solihull, Blackpool, Manchester, Ipswich and Llandudno.

Specialising in rheumatology, the senior registrar works as a locum and runs clinics for thousands of unsuspecting British patients, who had no idea of the role he played in Saddam’s brutal regime.

In 1992, aged 27, he was party to the Iraqi regime’s deadly treatment of prisoners in Baghdad.

Al-Byati, now 46, worked for the country’s secret intelligence unit for 15 months after qualifying as a junior doctor.

It was part of the military service required by the regime, and Al-Byati claims he ‘had no choice’ over the matter.

The intelligence agency had a top-security prison in Kadhimiya, where Saddam was eventually executed in 2006.

It was there that Al-Byati was taken when the vicious guards realised they had gone too far and risked having a death on their hands.

Speaking to the Mail last night, the doctor at first tried to play down the extent of the prisoners’ injuries. He said: ‘There were some bruises, some cuts.’

But on further probing, he admitted that three men he treated had been left ‘for one or two days’ without treatment after vicious beatings.

'Not bleeding much because it was one day, two days before they called me. They looked like somebody who had a big accident.

He said: ‘There were some bruises, some cut wounds, mostly on the arms. Not with a knife, probably with a wood thing.

‘There are two men with you and the prisoner can’t even look at you. I can’t do more than dressing, only simple suturing.

'I said two people need to be transferred to hospital.

‘What’s going to happen after that? Are they going to torture them? I would say yes but I haven’t seen with my own eyes. It’s just assumption.’

Asked whether he thought the prisoners had survived, Al-Byati said: ‘They were alive when I left,’ and then laughed.

The doctor said he would have been killed or his family harmed if he had tried to alert humanitarian groups.

He told no one, and continued working in Baghdad until 1995, before departing for Jordan and then Libya.

In 2000 he moved to the UK to complete British medical qualifications, and then worked in hospitals as a well-paid registrar.

Everything was going swimmingly until 2007, he said, when his visa lapsed and the Home Office blocked his application for a replacement.

So Al-Byati decided to apply for asylum, on the grounds that the lives of his wife Yousra and children, now aged seven, 12 and 17, will be at risk if they are forced to return to Iraq.

From 2007, Al-Byati could not work for a year, he said, but was able to claim benefits and a council house. He then applied for a work permit and it was granted.

He said: ‘The money as a locum is very good. I have not worked for the past three months but I have saved.’

But Al-Byati said life now is ‘very difficult’. He said: ‘I can’t go out of this country. I want to see my 70-year-old mother and my brother in America. My wife has family in Jordan, she wants to go there. But we have no passport. It’s like my wife and children are in prison.

‘I can’t get a job, I can’t progress. To be honest, I’m very upset.’ Al-Byati said he does not consider himself to be a war criminal or to have colluded in the atrocities.

Neither does he regret the 15 months he worked for the secret service.

His message to the Home Office is unequivocal: ‘If you think I’m a collaborator, reject me. I’ve been in this country for 11 years. If anything was wrong they would refuse my application at the first time.

‘I’ve done my job as a doctor, nothing more. So if you think that treating people who were tortured was a crime, it’s up to you. For me, I was the one who was helping them.’